The tower as disclosed and claimed in the above-noted '890 application has seed flow sensors for the secondary streams of air and seeds that are located at the distribution head of the tower, preferably within the head itself. Likewise, the tower of that application can be adapted for use in tram line farming practices wherein one or more of the hoses carrying secondary streams to the openers can be selectively shut off so that no seeds are planted for that particular row. As in the case of the sensors, a valve for the tram line hose is located at, and preferably within, the distribution head. In addition, a special housing immediately below the distribution head encloses and protects delicate wiring and sensitive connectors associated with the various sensors and valves of the tower.
A tower in accordance with the principles of the present invention carries forward with, and in some instances further refines, the above-noted aspects of the '890 application. In addition, a tower in accordance with the principles of the present invention introduces a simplified, modular construction for the distribution head wherein discharge outlets for the secondary streams are presented by individual outlet modules that can be quickly and easily installed and removed from the distribution head on an individual basis. There is no need to disassemble the entire distribution head in order to replace a single outlet module. Among other things, this design facilitates manufacture, makes it easy for the farmer to remove, replace, and exchange individual modules, permits significant flexibility as to which, if any, of the discharge outlets will be devoted to a tram line, and provides the farmer with many choices as to which modules to install for carrying out different functions. The outlet modules may take a variety of different forms and carry out a variety of different functions in addition to their primary functions of serving as a means of directing secondary streams of seeds and air from the distribution tower. They need not include any flow sensors or shut-off valves at all.
In a preferred form of the invention a flow sensor for each secondary hose is incorporated into the outlet module itself so that the sensor forms a part of the distribution head. Likewise, at least certain of the outlet modules may have a shut-off valve incorporated into the body of the module so that the distribution head can be easily adapted for shutting off one or more of the secondary hoses by simply installing the appropriate valve-equipped module(s). An electrically operated motor can be provided for each valve as part of the module, and such motor can be selectively detached from the valve to permit manual valve actuation if desired.
The outlet modules are designed to be installed and removed without the use of tools. In a preferred embodiment a latch for releasably retaining a module in its seat within the distribution head includes a spring-loaded barb on the body of the module that cooperates with structure adjacent the seat to hold the module in place. By manually depressing the barb to a releasing position, the module may be easily withdrawn from the seat.